Add prominent website callout to README

Added a clear, visible link to the GitHub Pages website at the top of the README to make it easy for visitors to find the online version of the book.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: DavidLiedle

README.md

@@ -1,5 +1,9 @@
 # The Io Programming Language: A Comprehensive Guide
 
+> **📖 [Read the book online](https://cloudstreet-dev.github.io/The-Io-Programming-Language/)**
+>
+> The complete book is available as a beautiful, searchable website at https://cloudstreet-dev.github.io/The-Io-Programming-Language/
+
 ## About This Book
 
 This book provides an in-depth exploration of the Io programming language, designed for experienced programmers who want to understand prototype-based object-oriented programming. Through detailed comparisons with mainstream languages like JavaScript, Python, Ruby, and Java, readers will gain practical insights into Io's unique paradigm.